It is best to make sure that you are in compliance by speaking directly to Microsoft.

From your description, your primary node(s) needs to be licensed for all cores, and...

Is the database in question part of the AG, and is it properly synchronized with the secondaries?

Instead of re-inventing the wheel, take a look at these tools:

https://dbatools.io/commands/

Assuming SQL mail is working, it has to be the configuration of the alert.

I have this in a script that is part of the default set of scripts...

You need to add the notifications to the alerts.


EXEC msdb.dbo.sp_add_notification
@alert_name = N'Whatever name you gave it',
@operator_name = N'DBA',
@notification_method = 1;
GO


@Message_id = 0, that is nothing.  Try making that 1480.